Stable polypeptides associated with the 250S mengovirus-induced RNA polymerase structure

Area of Science:

• Molecular Biology
• Virology
• Biochemistry

Background:

• Viral RNA polymerase is crucial for viral replication.
• Understanding the composition of viral RNA polymerase aids in comprehending viral infection mechanisms.

Purpose of the Study:

• To identify and characterize the polypeptide components of the viral RNA polymerase.
• To investigate the stability and synthesis of viral RNA polymerase subunits during infection.

Main Methods:

• Partial purification of the 250S RNA polymerase structure using velocity sedimentation and isopycnic separation.
• Pulse-chase experiments to track polypeptide incorporation and stability.
• Inhibition studies using cycloheximide to assess protein synthesis turnover.

Main Results:

• A 40,000 dalton host polypeptide is associated with the 250S RNA polymerase.
• A 56,000 dalton polypeptide (polypeptide E) synthesized during the eclipse phase is stably incorporated into the 250S viral RNA polymerase structure.
• This 56,000 dalton polypeptide is not rapidly degraded, suggesting stability.
• Cycloheximide treatment did not affect in vitro viral RNA polymerase activity, supporting the hypothesis of a stable polymerase polypeptide.

Conclusions:

• The stable 56,000 dalton polypeptide (polypeptide E) synthesized early in infection is a strong candidate for the viral-specific RNA polymerase polypeptide.
• Viral RNA polymerase components may be stable and not subject to rapid turnover in infected cells.